Yamaha TRX850 Enthusiasts Forum

Mostly OK! That is nice.
fairly easy to work on...so far.

No inlet valves below .15 mm, no exhaust below 0.20
Camchain tensioner still has 7 mms till Last Position.
Now the cams are late by 6 degrees or so... will be the cam chain + chain guides wear.
How many teeth on the sprockets? 34?

The exhaust cam was 1 tooth late!
We were with 3 men, and sure enough!
Compression rates 8.3 both, very equal, with a slow 200 RPM starter engine. That really is not much. Both of them.

We try tomorrow with the changed exhaust cam setting, but I feel that wont change much compressionwise.....hooking up a car battery will make the difference?

Well, before opening up she ran OK IMHO.....I only did a short spin till 80 miles/hr, tried till 6000 RPM. in 4 or 3...I liked it very much. [my bike is a 50 HP German boxer...also know the Honda NTV...] No flat spots, strange idling but only 1 cylinder affected: way too rich. Can be anything.

Vacuum operated fuel tap wont close, but membrane is not leaky it seems.

I have seen a GLIMPSE of those darn mixture screws....


WIEMER + IGOR [the owner]

Well,

Made a spin around town.
The only change that we made is putting the ex cam 1 tooth forward....that makes about 20 crank degrees, and that is an awful lot.
We could hardly believe it was 1 tooth late.....but there MUST be an effect in riding ????
The bike has Shark F1-mufflers, and main jets #144. We closed the extra hole in the airbox some PO had made.

Before.. the TRX felt like some big Guzzi of the 70 -ties: lots of constant torque. [they delivered a typical 65 HP I believe].
I didnt surpass the 6000 RPM mark, and 5 gear felt good for the highway run.
..but that was a short spin. I regret that.

- sound change.
- power loss at 1000-3000 RPM.: the diesel/Guzzi trait has gone. Now it is easier to drive 3000 RPM in 3. [before it needed the absolute minimum of throttle to do so]
- from 4500 on there really is happening something, 5 even more, 6000 RPM in 3 with full throttle feels dangerous for an old fart like me. Lifting the front wheel should be easy...
It has become a rocket, the 80 HP's definitely are there! At 120/hour the 4 gear feels appropriate.
- the right carb problem is still there of course. Nothing changed & nothing to see there. Let us try syncing them.

I am amazed that before altering the ex cam timing the bike [we are not quite familiar with] felt so normal-ish...

My son wants to have her back now...

Wiemer & Igor



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